The present invention relates to a dovetail cutting device and a method for the manufacture of dovetailings (fingers) on the faces or ends of boards that are to be jointed face to face in a continuous manner or individually.
In conventional methods for the manufacture of dovetail jointing or finger jointing, boards of various lengths are stacked on edge on a cutting table, with one of their respective faces or ends aligned to one another. The aligned faces of the stack of boards are then cut at a right angle relative to the length of the boards, for example, with a circular saw to yield a straight face or end of the stack of boards. Then the dovetailings (fingers) are cut into the boards to a length of 10 to 30 cm by a profile cutter. The dovetailings (fingers) are subsequently pasted with glue. In a further step, the boards are aligned with their respective opposite faces or ends and are provided with dovetailings (fingers) by a second set of machines or profile cutters. The dovetailings (fingers) are also pasted with glue. The dovetailings of the boards prepared in the above described manner are then joined together and pressed in a dovetail jointing press during the hardening of the glue.
The method of the prior art requires the use of two profile cutters for the two faces or ends of the boards. Therefore, the geometry of the two individual profile cutters must be exactly adjusted in order to ensure a perfect and exact jointing of the boards, especially to avoid gaps between the joints or crushing of the joints. It is especially important to have a perfect fit in order to ensure proper pasting. The jointing of the boards must be such that the static load and mechanical strength characteristics of the joint are comparable to that of natural wood. A typical problem of having two cutting tools for dovetailing is that the sharpening of the cutting tools usually results in misaligned and misadjusted geometries of the tools, thus requiring a time-consuming readjustment of the respective tool geometries and therefore long and costly shut-down periods. The double set of the cutting tools also requires significantly more space. It has been suggested to provide the cutting table with means for rotating it about 180.degree. for boards that are 5 m or longer. This would allow for the use of only one cutting tool since the boards could be cut with the same cutter in the same position. However, this results in even greater space requirements and a throughput reduction.
It is therefore an object of the present invention to provide a dovetail cutting device that requires less space and is less expensive, while at the same time yields a higher throughput and is easier to operate.